rfc7230 compliance, limits, and tests for basic_parser_v1:

New parser set_option function for controlling independent size limits
on headers and body. By default request and response parsers are set up
with reasonable limits to prevent resource exhaustion attacks.

* Parser adheres strictly to rfc7230
* Increased test coverage
* Headers and body maximum size limit options

doc/quickref.xml

@@ -39,6 +39,11 @@
             <member><link linkend="beast.ref.http__streambuf_body">streambuf_body</link></member>
             <member><link linkend="beast.ref.http__string_body">string_body</link></member>
           </simplelist>
+          <bridgehead renderas="sect3">Options</bridgehead>
+          <simplelist type="vert" columns="1">
+            <member><link linkend="beast.ref.http__body_max_size">body_max_size</link></member>
+            <member><link linkend="beast.ref.http__headers_max_size">headers_max_size</link></member>
+          </simplelist>
           <bridgehead renderas="sect3">Type Traits</bridgehead>
           <simplelist type="vert" columns="1">
            <member><link linkend="beast.ref.http__is_Body">is_Body</link></member>